Master of Divine Mother Ambika is called as Ambika-Nath. Though they are non-dual, still he stays apart, just to give meaning to His Lordship. He himself assumes the playful figure of feminine nature and dwells with him in masculine appearance. Whatever is visible in the world, and whatever is felt by knowledge acquiring senses, that is nothing but the result of merciful glance of Bhagvati. In the form of mother nature, She affectionately takes care of all living beings. Being master and controller of this mother nature, the Supreme Lord is known as Ambika-Nath.

All movements in this creation are directed by Lord Shankar. Complete show of nature depends upon its prime support called Purusha. Shvia performed austerities to attain Ambika as his wife, while Bhagvati became even Aparna by performing severe austerities to attain him as husband. Out of many names of Parvati, this name Ambika is prominent in Halayudha-Kosha—
आर्याऽम्बिका मृडानी हैमवती पार्वती गौरी।
Thus Mother Gauri’s Shankar is named as Ambikanath. Shri Bhaskar Roy explains this name as under—

नाथसि हिमाचलमुमां मनसा तां नाथसेऽथ तन्नाथः।
प्रकटोऽसि देविकायां लिंगे तेनाम्बिकानाथः॥

Purport: You ask for Ambika from Himalaya, you desire for her in your heart, you are her husband, and you are residing as Ambika- Natheshwar at Devika-krita, therefore you are called as Ambikanath.

This description is conceived because the word ‘Nath’ has lots of meanings. In spiritual terms, material nature can execute nothing without association of soul power. Nature is fully controlled by God. Here is a denial of Sankya Philosophy which says that nature itself is omnipotent. Lord Shankar is master of both forms of Ambika, whether individual or cosmic.

An eccentric meaning can be accomplished from this name. Ambika is mistress of whom, that Bholenath is called as Ambikanath. Actually wife is the chief in the house. Shiva is called Ambikanath because he is the subject of sentiments for Ambika.

Shankaracharya is offering a prayer in Shivanand Lahri in order to get Shiva’s favor —

कल्याणिनं सरसचित्रगतिं सवेगं सर्वेंगितज्ञमनघं ध्रुवलक्षणाढ्यम्।
चेतस्तुरंगमधिरुह्य चर स्मरारे नेतः समस्तजगतां वृषभाधिरुढ ॥

Purport: O conqueror of lust! O leader of congregation! benefactor with all auspicious signs whose every step is pleasing and amazing, who marches speedily, who understands every gesture, who follows strict discipline, may that Lord Ambikanath wander through out the world, riding on the horse of my mind.
Knowing absolute Brahman by holding spiritual consciousness is the true form of worship of Ambika-Nath.